Black and white photos and line art images are available from many sources for integration into documents. In electronic document creation this is easily done on several possible levels, including the derivation of the black and white image by scanning. Alternatively, a large number of computer systems still produce images that are black and white. In either case, in the production of colored documents, it is often desirable to convert black and white images to colors to produce a visually pleasing result. In broader terms however, it is desirable to convert lines or background of any color to other colors on a differentiated basis.
U.S. Pat. No. 4,608,596 to Williams et al. discloses a system for the colorization of monochrome video frames under operator control including a video color encoder. The encoder has a luminance input and a plurality of color component inputs. The luminance signal is derived from a monochrome video signal, and an operator assigns color component signals to selected regions of pixels of the video frame. The color video output of the color video encoder can be displayed and recorded.
U.S. Pat. Nos. 3,706,841 and 3,784,736, both to Novak, disclose methods for converting black and white monochrome images to multi-color pictures. The method uses a video camera to scan a black and white monochrome image. Luminance values of the scanned black and white image are combined with selected color signals to create a colorized image. Additionally, in the '736 patent, the image can be separated into foreground and background memories, which may be operated on independently.
U.S. Pat. No. 4,862,256 to Markle et al. discloses a method of coloring a black and white video signal in which different parts of a frame are assigned a particular color on the basis of gray levels or luminance values.
Japanese Patent No. 57-99088 to Watanabe discloses a system for providing a simulated color picture from a black and white picture. In the system, a color subcarrier signal is arbitrarily selected and synthesized to provide a simulated color picture.
Japanese Patent No. 60-141093 to Mizuguchi discloses a method of coloring a picture. The picture is converted to a video signal and a luminance signal is separated from it. As a result of a coloring process executed on the basis of a profile picture formed from the video, a chrominance signal is output, and mixed with the luminance signal.
All the references cited hereinabove are specifically incorporated by reference.